class Employee(object):
    def __init__(self, name, salary):
        self.__name = name
        self.__salary = salary

    def get_name(self):
        return self.__name
    def set_name(self,name):
        self.__name = name
    def get_salary(self):
        return self.__salary
    def set_salary(self,salary):
        if salary < 0:
            raise ValueError("salary must be positive")
        else:
            self.__salary = salary
    def display_info(self):
        print(f"姓名：{self.__name},薪资为{self.__salary}")

class Manager(Employee):
    def __init__(self, name, salary,department):
        self.__department = department
        super().__init__(name, salary)
    def get_department(self):
        return self.__department
    def set_department(self,department):
        self.__department = department
    def display_info(self):
        print(f"姓名：{self.get_name()},薪资为{self.get_salary()},部门为{self.__department}")

man = Manager("zs",2000,"IT部门")
man.display_info()
man.set_salary(-2000)